Here is a suggestion.
If you have a spot that you can comfortably (without pissing off the Missus) cut a 6" hole in the floor upstairs, scrounge up a self contained furnace blower (motor built in) and find a suitable spot in the basement and hook this puppy up to suck the warm air near the stove and blow it up through a light weight aluminum duct pipe to the upstairs.
You could do this in such a way that it would be very unobtrusive and then just store the fan in the summer.
Do a nice register in the upstairs floor and hook everything up neat and tidy.
Just some thoughts.
Out here in the PNW we rarely see boilers, but more forced air stuff.
Snowy
If you have a spot that you can comfortably (without pissing off the Missus) cut a 6" hole in the floor upstairs, scrounge up a self contained furnace blower (motor built in) and find a suitable spot in the basement and hook this puppy up to suck the warm air near the stove and blow it up through a light weight aluminum duct pipe to the upstairs.
You could do this in such a way that it would be very unobtrusive and then just store the fan in the summer.
Do a nice register in the upstairs floor and hook everything up neat and tidy.
Just some thoughts.
Out here in the PNW we rarely see boilers, but more forced air stuff.
Snowy